I have a 1993 Mercedes Benz 400 SEL 140
The car can run for days with no problem.
I was able to be there one time when the
car stopped running there was no injector pulse
no ground to the fuel pump relay, there was spark.
The were CAN system codes in the LH module EA and EZL
not communicating with LH module. If you removed LH module
and plug it back in car will start back up and run for another
3 days. That was only time I was able to see the car not start.

History the car was in and out of many Mercedes Dealers
and specialist.
The EA and Mass air flow sensor were replaced at another shop